1. Field
Exemplary embodiments disclosed herein relate to a light emitting diode (LED) driving apparatus, a LED driving method, and a computer-readable recording medium. More particularly, exemplary embodiments disclosed herein relate to a light emitting diode driving apparatus, a LED driving method, and a computer-readable recording medium which can reduce heat of a switching component and control independently each of a plurality of LED arrays.
2. Description of the Related Art
Since a liquid crystal display (LCD) is thin and light, and has a driving voltage and power consumption which is lower than other display apparatuses, liquid crystal displays are widely used. However, since the liquid crystal display cannot emit light by itself and is a non-light emitting component, the liquid crystal display needs a separate backlight unit to supply light.
Cold cathode fluorescent lamps (CCFLs), light emitting diodes (LEDS), etc. are often used as a backlight light source of the liquid crystal display. The cold cathode fluorescent lamps may cause environmental pollution because of mercury. Further, cold cathode fluorescent lamps have a slow speed of response and lower color reproducibility, and are not suitable to make lighter, slimmer and smaller LCD panels.
In contrast, the LED does not use environmentally harmful substances and is therefore environmentally friendly, and has the advantage of being impulse-driven. Further, since LED technology has excellent color reproducibility, can randomly change luminance, color temperature, etc. by adjusting the amount of light of red, green and blue LEDs, and is suitable for manufacturing lighter, slimmer and smaller LCD panels, the LED is often used as a backlight light source of LCD panels. In an LCD backlight employing LEDs, in order to improve the image quality and to reduce power consumption, current being supplied to the LEDs is varied corresponding to brightness information of images.
Recently, display apparatuses with high definition and built-in 3D functions use an LED backlight unit configured of a plurality of channels (or a plurality of LED arrays). A current source apparatus which can independently control current of each of the channels is required to drive the LED backlight unit configured with the plurality of channels. For current control, a conventional LED backlight unit uses a switch mode type circuit or a linear mode type circuit.
The conventional switch mode type circuit is provided with a complete power conversion circuit for each LED array, and can perform current control regardless of variation of the forward voltage Vf of each LED array. However, since power components having the same function are used redundantly, there is a drawback that the size and price of the circuit are increased.
The conventional linear mode type circuit is provided with a variable voltage source apparatus to control total voltage thereof and linear switches to separately control current of each channel. Therefore, the size of the conventional linear mode type circuit is relatively small and the price of the entire circuit is reduced, as compared to the conventional switch mode type circuit. However, since an increase in a variation of the forward voltage Vf of each LED array causes a corresponding increase in heat of the linear switch, efficiency may be reduced and a reliability problem may occur.